1. Field of the Invention
Embodiments of the invention relate to an organic light emitting diode display.
2. Discussion of the Related Art
An organic light emitting element used in an organic light emitting diode (OLED) display has a self-emission structure in which a light emitting layer is formed between two electrodes. The organic light emitting element injects electrons from a cathode corresponding to an electron injection electrode and holes from an anode corresponding to an hole injection electrode into the light emitting layer and emits light when an exciton formed by a combination of the injected electrons and the injected holes falls from an excitation level to a ground level.
The OLED display using the organic light emitting element may be classified into a top emission type OLED display, a bottom emission type OLED display, and a dual emission type OLED display depending on an emitting direction of light. The OLED display may be classified into a passive matrix type OLED display and an active matrix type OLED display depending on a driving manner.
In the OLED display, when a scan signal, a data signal, a power, etc. are supplied to a plurality of subpixels arranged in a matrix form, selected subpixels of the plurality of subpixels emit light to thereby display an image.
Each of the subpixels includes a transistor unit including a switching transistor, a driving transistor, and a capacitor and an organic light emitting diode including a first electrode connected to the driving transistor of the transistor unit, an organic light emitting layer, and a second electrode.
In the OLED display, each of the subpixels generally has a different luminance so as to obtain a white balance of a unit pixel including a red subpixel, a green subpixel, and a blue subpixel. However, in a related art OLED display, lifetimes of the red, green, and blue subpixels constituting the unit pixel are different from one another. Thus, as driving time of the related art OLED display increases, a luminance of the related art OLED display is reduced or the problem of a movement of a color coordinate occurs.